(Code Geass S2 Ep.21 "Ragnarok connection" dialogue analysis)
This analysis was planned a while ago, but accidentally started earlier than planned with an Youtube comment, answering why in the culmination of the series in a dialogue with his parents, Lelouch didn't bring up Mao. Mao was a person who's seen "the world without lies" which could've been important to mentions by Lelouch as an argument. So...
Why Lelouch didn't bring up Mao?
Because they have discussed family matters and Mao had nothing to do with it. Even though the "Ragnarok plan" is a part of an argument, you still can't deny that this is a talk about
"what you, my parents did wrong", one way or another.
There's an important trauma that Lelouch has with his and Nannally's whole life going to hell, and let's just say that the time is extremely limited for him to talk. The game was about to end one way or another with Charles saying:
"What of it? The Ragnarok connection has begun. There's nothing you can do about it."
That's what they all came for (Charles, Marianne, C.C and Suzaku), they all came for the ending of time (to start it, to stop it), and only Lelouch is here to talk about Nannally 'till the last moments and solves the whole game puzzle as a little side quest. What's important to him is family. That's why he always brings the talk back to this matter, that he tried to comprehend and got disappointed in his own parents during this talk.
"YOU JUST TOLD ME! You said that the dead would rejoin the living!" - this is when he realized that his parents don't have an excuse he hoped to hear, they just really don't care.
And so the movie culmination got out of hand, they talk about the future, but in reality they all just fight for their personal reasons.
- Charles and Marianne want a gentler place for themselves,
- Lelouch wants one for Nannally,
- Suzaku follows him in honor of Euphi's dreams,
- C.C betrays Marianne because she fell for her son.
That's why it's no longer an honest argument with a goal to change opponents minds, but rather a battle of interests. All the smart talk end with simple:
[Charles] - What if it? I don't care that your arguments are stronger, cause I still got it my way.
[Lelouch] - Oh really? Then I'll get it to be my way by the power I fetched recently. Just watch me going!